How many peptide bonds are present in a polypeptide that contains 45 amino acids?

44 peptide bonds. There are n-1 peptide bonds, where n is the amount of amino acids. This is because there are two termini on a polypeptide that makes it "hang off." It is like linking up a chain, if there are two that must bond together then they cannot bond with another chain, therefore there is always one less bond than the total amount of amino acids.